Rechargeable battery power source with gas-pressure switch

ABSTRACT

The source comprises a battery of the type adapted to produce an increased gaseous pressure when the battery is fully charged such as a nickel-cadmium battery. The battery includes a cylindrical jacket having top and bottom walls and the control device is sealingly connected to the top wall and is adapted to be connected to a battery charging device for controlling the operation of the device to prevent overcharging of the battery per se. The control device includes a housing having a pressureresponsive diaphragm therein which is adapted to move from a first position to a second position in response to the increased gaseous pressure produced by the battery when it is fully charged. A switch is operable between a closed state for energizing the charging device and an open state for deenergizing the charging device. Connecting means is provided for connecting the switch with the diaphragm so that the switch is moved to the open state in response to movement of the diaphragm to the second position. A passage connects the interior of the battery with the diaphragm so that the increased gaseous pressure within the jacket moves the diaphragm from the first to the second position.

United States Patent 1191 Frezzolini et a1.

1451 Nov. 27, 1973 RECHARGEABLE BATTERY POWER v 57 ABSTRACT SOURCE WITH GAS-PRESSURE SWITCH The source comprises a battery of the type adapted to [75] Inventors! Jam i' ;'J leS J- produce an increased gaseous pressure when the bat- 1 fl both of g tery is fully charged such as a nickel-cadmium battery. The battery includes a cylindrical jacket having top [73] Asslgnee. 232312 121 jElectlomc Haw and bottom walls and the control device is sealingly connected to the top wall and is adapted to be con- [22] Filed: May 23, 1972 nected to a battery charging device for controlling the operation of the device to prevent overcharging of the App! 256123 battery per se. The control device includes a housing having a pressure-responsive diaphragm'therein which [52] U.S. Cl. 320/46, 136/181, 200/83 B s ad p to move from first p sition to a second [51] Int. Cl. H01m 45/04, H02j 7/00 position in p s to the n r as d gas ous pressur [58] Field of Search 320/46; 200/83 B; produced y the battery when it is fully a g d. A

' 136/181 switch is operable between a closed state for energizing the charging device and an open state for deener- [56] References Cit d gizing thecharging device. Connecting means is pro- UNITED STATES PATENTS vided for connecting the switch with the diaphragm so 1 that the switch is moved to the open state in response 3,081,366 3/1963 Belove 320/46 ux to movement ofthe diaphragm to the Second position 2,204,101 6/l940. Fumagall1.. 320/46 X 3,490,342 1 1970 Reis zoo/s3 B A Passage cmnicts of the battery the diaphragm so that the increased gaseous pressure FOREIGN PATENTS OR APPLICATIONS within the jacket moves the diaphragm from the first 863,742 3/1961 Great Britain 200/83 B to the second position.

Primary Examiner- J. Miller 3 Claims, 5 r i g g r Assistant Examiner- Robert J. Hickey Att0meyPaul Fields t 516 152 I03 I07 J 134 2 10/ I38 //////l /l\ l /l///V PATENTEUHUVZ? 1975 F IG.- 2.

RECHARGEABLE BATTERY POWERISQURCE" WITH GAS-PRESSURE SWITCH This invention relates .to. a ,rechargeableebattery power source and, more particularly, pertains to abattery power pack in whichthe possibility of overcharging the batteryis eliminated. 3

' Presently, electrically.poweredportabledevicestsuch as flashlights, electric flashguns for cameras, razors and the like are manufactured with an integral-power pack or battery power source which includes both a rechargeable battery and a charging circuit. Undernormal operation, as the stored energy in thebatterybegins to decrease, the charging circuit is connectedtoan external source of energy which-supplies the power necessary to charge the battery. Although so-called nickel-cadmiumbatteries would be ideal asthepower pack becauseof their efficiency and capability, aproblem is encountered in chargingsuch batteries.

' To be more specific, most power packsofthetype under consideration utilize a charging circuit which is adapted to sense some characteristic of the battery such as the potential. Thus, as the potential of the battery increases the charging circuit decreases. the energy supply to the battery and finally ceasesto supply energy when the battery potential reaches the rated value to prevent overcharging of the battery. However, inherent in the properties of nickel-cadmium-batteries isthefact that such batteries have no discernible repetitive voltage characteristics. Hence, sensing the potential of the battery is useless as a means of controlling the charging of the. same. Moreover, and of greater importance, is

A further object of the invention is the provision of a battery power source having a reliable control means for deenergizing a charger when the battery is fully charged.

Accordingly, a rechargeable batterypower source constructed in accordance with the present invention comprises a battery of the type adapted toproduce'an increased gaseous pressure when the battery is fully v charged. The battery includes a cylindrical jacket having a top and bottom wall and control means is se'al-. ingly connected to the top wall and is adapted to be connected to a battery charging device for controlling the operation of said device to prevent overcharging of the battery. The control means comprises a housing having a movable pressure-responsive "diaphragm. therein. Additionally, a-switch isprovidedwhich-is operable between a closed state for energizingthecharging device and an .open state for deenergizing the charging device. Connecting means connects the switch with the diaphragm and is adapted'tomove the switch to the open state in response to movement of the diaphragm: in a first direction. A passage connects'the interior of the battery with the diaphragmso that the ingof thebattery.

increased gaseous pressure withinl'the jacket moves the diaphragm in the .fii'st direction to cause deenergization of the charging device thereby preventing overcharging of the battery. I

Other features and advantages'of the present invention will. become more'apparent from ac onsideration of the following detailed description when takenfin conjunction with the accompanying drawing, in which: FIG: l is an enlargedperspective view of a power source constructedinaccordance with thezpresentinvention; v

FIG. 2 is a sectionalview of the control device forming a part-of thepowerlsourceshown in FIG. 1;

3 FFIGLB is a toptplanview of'the diaphragm in the con- .trol. device :of {FIG-1 2;

.yyE-IG. 4 is arbotto rn plan view .thereof; and I i v FIGJS is a'part'ial sectional view'of a modified embodiment of ithe. control'device.

Before 'describinguthe. rechargeable battery power source of thepresent inventionindetail, it is believed that a discussion of the characteristics of nickelcadmium battery cells will facilitate an understanding and. an appreciation .of :.the present invention. Accord- :=ingly, asnoted hereinabove, a nickel-cadmium or socalled Nicad battery cell has no discernible repetitive voltage characteristics. However, at the end of the 'charging period of a nickel-cadmium battery, (i.e.,

whenthebattery isfully' charged) a gas is produced withinth'e batteryrThis gas, which is oxygen, increases thegaseous pressure within the jacket enclosing the chemical elements'of the battery. As the energy within \the battery is usedby an external device, the oxygen recombines with the elements within the battery so that '-=the gaseous pressure decreases. If, however, thebattery is overcharged, the gaseous pressure may increase to *such magnitudes astocause the battery to explode.

JT-hepresent invention-makes use of the fact that the .agaseous'pressure within the battery increases after the battery isfully'. charged, thereby to prevent overcharg- -More specifically, a rechargeable .battery "power source constructed" in accordance with the present invention isdesignated generally by .the reference numeral 10 in-the figures and includes a battery 12. The

. battery 12 is of the nickel-cadmium or Nicad type and includes a cylindrical metal jacket 14 having a top wall .16 and a bottom wall l8.As noted hereinabove,.the

' battery .12 will produce anincreased gaseous pressure 'withinthe jacket -14 when the battery is fully charged.

. Mounted on the top wall l6of the battery 14' is a conittrolidevicedesignated generally by the reference numeral 20 a'ndishown in detail in FIGS. 1 and 2. The convtroldevice' 20, as noted in greater detail hereinbelow,

. .is-connected to abattery charger or charging device 22 and is adapted" to control the operation of1the charger v 22'which supplies charging energy to the battery .12 .via alead 24". The charger. 22 may be any conventional bat- .tery charging circuit: The control device. '20 normally v causes the charger 22 to be energized thereby to charge 1 the battery. 12. However, when the battery 12 isfully charged the control device 20 senses the increased gaseouspressure within the battery corresponding ,tofull L chargev of the battery and operatestode-energize the charger 22 to prevent further charging of the battery.

ln='particular-, the control device-20 includes a sup- I port member 26-which may be fabricated from a metal such as steelorthelike'. The support memberl 26 includes a multi-faceted-peripheral wall 28 and a bottom wall 30 having a portion 32 which slopes downwardly toward the center of the support member and. a depending circular flange 34 connected to the portion '32. The flange 34 includes a through bore 36 the bottom within the recess 38 is an O-ring or gasket 40 which may be fabricated from rubber or the like.

' ber 26 is positioned on the top wall of the battery so that the bore 36 communicates with the vent opening 42. The diameter of the O-ring 40 is chosen to be slightly larger than the recess 38 so that the O-ring 40 will becompressed between the top wall 16 and the walls forming the recess 38 in the support member 28 whereby the O-ring forms a gas-tight seal between the vent opening 42 and the support member 28. The support member 28 is maintained in this position by a welded bead 44 which surrounds the flange 34. V

Received within the support member 28 is an insert 46 which may be fabricated from plastic or the like. The insert includes an upper reduced diameter portion 48 and a lower enlarged diameter portion 50. The insert 46 includes an annular recess 52 in the portion 50 defined in part by a central circular wall 54 having a height which is less than the height of the outer peripheral wall defining the enlarged portion 50. The insert 46 is provided with an enlarged diameter central bore 56 which communicates with a reduced diameter central bore 58 in the portion 48 and which define a seat 60 at their junction. The outer diameter of the circular insert 46 is sustantially equal to the inner diameter of the support member 26 so that the outer wall of the insert 46 abuts the inner wall of the support member 26. As shown in FIGS. 1 and 2, the support member 26 includes an upper lip portion 62 which is adapted to be crimped over the edge of the enlarged diameter portion 50 of the insert 46 to maintain the insert in place within the support member.

Received between the horizontal surface of the bottom wall 30 of the support member 26 and the lower edge of the insert 46 is a diaphragm designated generally by the reference numeral 64. Since the wall 30 supports the diaphragm, it may thought of as a supporting wall in the support member. The diaphragm is fabricated from a flexible and resilient material such as rubber and includes an upper circular member 66 and a lower sealing member 68. The member 68 includes an 4 enlarged diameter portion 50 'of the insert 46 to provide a gas-tight seal therebetween. Accordingly, the gas which exits from the interior of the battery 12 through the vent opening 42 and the bore 36 will be entrapped edge of which includes an enlarged recess 38. Received in the chamber below the diaphragm 64- and will be prevented from entering into the area above ther diaphragm.

A slot 80 is'provided in the upper reduced diameter portion 48 of the insert 46 and a switch 82 is received therein. A pin 84 extends through aligned bores 86 in the walls defining the upper reduced diameter portion 48 and a bore 88 in the switch 82 to maintain the switch in position. The switch 82 is a normally closed switch and is connected to the charger 22 by leads 90, which are connected to respective upstanding terminals 92 on the switch casing. Accordingly, with the switch normally closed the charger 22 will be energized to charge the battery 12.

However, the switch 82 includes a depending button or armature 94 which, when moved upwardly, causes the switch to open thereby de-energizing the charger 22. A circular or cylindrical member 96 is received in the cup-shaped member 76 and rests on the rivet connecting the member to the diaphragm 64, as shown in FIG. 2. The upper edge of the member abutsthe armature 94. Accordingly, if the diaphragm 64 is flexed upwardly themember 96 will likewise move upwardly thereby pushing the armature upwardly to open the switch. However, a biasing device in the form ofa spring 98 which abuts the seat 60 at one end and the cup 76 at the other end biases the diaphragm 64 downwardly so that the armature 94 is not moved inwardly under normal conditions thereby maintaining the switch 82 in the closed state so that the charger 22 remains energized.

In operation, under normal conditions when the charger 22 is charging the battery 12 the elements comprising the present invention will be in the positions inouter circular portion 70 connected to a central por-.

tion 72 by radial arms 74. Mounted on the upper surface of the member 66 is a cup-shaped member 76 which is retained in place by a centrally located rivet having an enlarged head 78 and which extends through the central portion 72 of the member 68, the upper circular member 66 and the cup-shaped-member 76. The cup-shaped member 76 may be fabricated from a met'al such as brass. The member 76 is of smaller diameter than the circular member 66. Additionally, the central portion 72 of the lower sealing member 68 is squeezed between the enlarged head 78 of the rivet and the cupshaped member 76 so that a gas-tight seal is produced dicated in FIG; 2. Accordingly, the switch 82 will be in the closed state so that the charger 22 will remain energized and supply charging energy to the battery 12. However, when the battery 12 becomes fully charged there is an increase in the gaseous pressure within the jacket 14 due to the liberation of oxygen. This increase in pressure will be exerted against the underside of the diaphragm 64 through the vent opening 42 and the bore 36 in the support member 26.

As the diaphragm 64 is flexed upwardly due to the increase in gaseous pressure, the member 76 will likewise travel upwardly against the bias of the spring 98. Hence, the member 96 will be carried upwardly thereby exerting an upward force on the armature 94 again recombines with the chemical elements withinthe battery to decrease the gaseous pressure within the battery. As the gaseous pressure decreases the force on the diaphragm 64 similarly decreases to that the diaphragm' again moves downwardly to its normal position. When the diaphragm reaches its normal position 1 the force on the armature 94 will be removed thereby permitting the armature to move downwardly whereupon the switch 82 closes to energize the charger 22.

Thus, charging energy will again be supplied to the battery.

Accordingly, a rechargeable battery power source has been provided which-utilizesnickel-cadmium cells or batteries and wherein absolute control over'the charging of the batteries is maintained.

A modified embodiment of the invention wherein a 1 different arrangement is utilized to connect thesupport member with the battery 12 is shown in FIG. 5, it being understood that the remainder of the control device is identical with that shown in FIGS. 1-4. Accordingly, only the differences are shown in FIG. 5.

Thus, the support member 126 of FIG. 5 includes a tapering wall portion 132 having a depending boss 134, a portion of which is threaded at 100 and forms a seat 102 at the junction of the threaded and unthreaded portions. The support member 126 is likewise provided with a bore 36 to permit passage of the fluid or gas from the battery into the interior of the control device.

The threaded portion 100 is threadedly received in a threaded opening 104 in a plate or disc 106. which has a diameter substantially equal to the diameter of the top wall 16 of the battery 12. Compressed between the disc 106 and the top wall 16 of the battery is a resilient O-ring 138 which has a diameter which is smaller than that of the disc. The O-ring 138 and disc 106 are coaxial with the battery so that the passages or bores 36 and 42 are aligned. The O-ring 138 provides a fluid-tight seal between the disc 106 and the battery to prevent any leakage of gas.

A collar 108 maintains the disc 106 in place on the battery. Thus, the collar 108. includes a top wall 101 having an enlarged central aperture 103 through which the support member extends. Additionally,the collar 108 includes a depending peripheral flange 105 which is connected to the battery by either a weld or solder bead 44. The collar 108 operates to center the disc 106 on the battery and to exert a downward force on the disc to compress the O-ring 138.

A nylon washer 107 or the like is compressed between the seat 102 and the disc 106 to provide a fluidtight seal between the disc and the support member.

When assembling the embodiment shown in FIG. 5, the collar 108 may be pre-tinned to facilitate soldering. The O-ring 138 is placed on the battery and the disc 106 is placed on the O-ring. The collar 108 is then placed on both the disc and the battery.ln practice, the diameter of the collar is made slightly smaller than the battery diameter so that the collar must be force-fitted to the battery. Accordingly, the collar is pushed down over the battery a sufficient distance to ensure compression .of the O-ring and, while the force is still applied, the collar is soldered (or welded) in place. The washer 107 is then placed on the threaded portion 100 of the support member and the support member is screwed into place until the washer 107 is squeezed between the seat 102 and the disc 106.

What is claimed is: 1. A rechargeable battery power source comprising a battery of a type adapted to produce an increased gaseous pressure when the battery is fully charged; said battery including a cylindrical jacket having top and bottom walls; control means adapted to be connected to a battery charging device for controlling'the operation of said device to prevent overcharging of said battery; sealing means for sealingly connecting said control means to said top wall of said battery jacket; said control means comprising a housing having a movable pressure-responsive flexible and resilient insulating diaphragm therein, a switch operable between a closed position for energizing the charging device and an open position for deenergizing the charging device, connecting means for connecting said switch with said dia phragm for moving said switch to the open position in response to movement of said diaphragm in a first direction, and a passage extending through said battery jacket and said housing connecting the interior of said battery with said diaphragm so that increased gaseous pressure within said jacket moves said diaphragm in said first direction to cause deenergization of the charging device; said diaphragm normally residing in a second position corresponding to the closed position of said switch, and being adapted to be moved in said first direction to a first position by said increased gaseous pressure to cause said switch to move to the open position, said diaphragm including a cup-shaped member connected with said switch, a seat in said housing, a spring in said housing abutting said seat at one end and said cup-shaped member at the other end to normally bias said diaphragm to the second position whereby said switch is moved to the closed position, said diaphragm further including an outer peripheral portion, said housing further comprising a support member having a support wall for supporting said outer peripheral portion of said diaphragm, said passage comprising a vent opening in said top wall of said battery and a bore in said support member to provide for the communication of said increased gaseous pressure with said diaphragm, said sealing means comprising a disc threadedly engaged with said support member, and a compressible O-ring compressed between said disc and said battery top wall and surrounding said vent and said bore.

2. A rechargeable battery power source as in claim 1, in which said sealing means further comprises a collar surrounding said disc and exerting a force on said disc in a direction to compress said O-ring, and means for connecting said collar to said battery.

3. A rechargeable battery power source as in claim 2, and means for sealing said support member to said disc in a gas-tight seal. 

1. A rechargeable battery power source comprising a battery of a type adapted to produce an increased gaseous pressure when the battery is fully charged; said battery including a cylindrical jacket having top and bottom walls; control means adapted to be connected to a battery charging device for controlling the operation of said device to prevent overcharging of said battery; sealing means for sealingly connecting said control means to said top wall of said battery jacket; said control means comprising a housing having a movable pressure-responsive flexible and resilient insulating diaphragm therein, a switch operable between a closed position for energizing the charging device and an open position for deenergizing the charging device, connecting means for connecting said switch with said diaphragm for moving said switch to the open position in response to movement of said diaphragm in a first direction, and a passage extending through said battery jacket and said housing connecting the interior of said battery with said diaphragm so that increased gaseous pressure within said jacket moves said diaphragm in said first direction to cause deenergization of the charging device; said diaphragm normally residing in a second position corresponding to the closed position of said switch, and being adapted to be moved in said first direction to a first position by said increased gaseous pressure to cause said switch to move to the open position, said diaphragm including a cup-shaped member connected with said switch, a seat in said housing, a spring in said housing abutting said seat at one end and said cup-shaped member at the other end to normally bias said diaphragm to the second position whereby said switch is moved to the closed position, said diaphragm further including an outer peripheral portion, said housing further comprising a support member having a support wall for supporting said outer peripheral portion of said diaphragm, said passage comprising a vent opening in said top wall of said battery and a bore in said support member to provide for the communication of said increased gaseous pressure with said diaphragm, said sealing means comprising a disc threadedly engaged with said support member, and a compressible O-ring compressed between said disc and said battery top wall and surrounding said vent and said bore.
 2. A rechargeable battery power source as in claim 1, in which said sealing means further comprises a collar surrounding said disc and exerting a force on said disc in a direction to compress said O-ring, and means for connecting said collar to said battery.
 3. A rechargeable battery power source as in claim 2, and means for sealing said support member to said disc in a gas-tight seal. 